Figure 6. cAMP signaling by dCIRL.
(a) Example current recordings from wildtype lch5 neurons during only mechanical (upper panel) and combined mechanical-light stimulation (lower panel) demonstrate the suppressive effect of cAMP elevation by bPAC on the mechanically-evoked action current frequency. (b) Protocol for combined mechanical stimulation and optogenetic cAMP production via bPAC photoactivation. (c) The mechanosensory response (action current frequency) of wildtype lch5 neurons is decreased to the level of dCirlKO larvae by increasing cAMP concentrations through light-induced bPAC stimulation (blue bar). In contrast, dCirlKO neurons are unaffected by light stimulation. Data are presented as mean ± SEM, n denotes number of animals. iav-GAL4>UAS-bPAC; wt (black, n = 9); iav-GAL4>UAS-bPAC; dCirlKO (gray, n = 10); iav-GAL4; wt (brown, n = 9). (d) Pharmacological inhibition of adenylyl cyclase activity using 100 µM SQ22536 rescues mechanically-evoked action current frequencies in dCirlKO lch5 neurons. Data are presented as mean ± SEM. Event frequency at 900 Hz without inhibitor: Control: 74.9 ± 8.67 Hz; dCirlKO: 43.88 ± 10.48 Hz; p=0.0287, Student’s t-test. Event frequency at 900 Hz with inhibitor: Control: 82.63 ± 10.51 Hz; dCirlKO: 57.25 ± 13.69 Hz; p=0.2103; n = 8 per genotype and condition.